How can I prevent it?

Prevention of athlete's foot begins with good, regular self-care. This includes drying your feet well after bathing, not wearing the same shoes every day so they have adequate time to dry out, wearing cotton socks and changing them every day.

If you've contracted athlete's foot, there are steps you need to follow to prevent re-infection. This includes completing the entire course of treatment with an antifungal medication as directed, using separate towels to dry the infected areas of your feet, and washing all shoes, socks, cloths, and bed sheets at 60º C/140º F and with bleach to thoroughly kill the fungus.

More prevention tips

You can help prevent athlete's foot by:

washing your feet daily, including the area between your toes, with warm water and a gentle soap
drying them well afterwards, paying special attention to the area between your toes
changing your socks every day (twice if you're prone to sweating) and washing dirty ones at 60º C
wearing socks made of natural, breathable materials, such as cotton or wool
letting your feet breathe by wearing light, open shoes or sandals
giving your shoes at least 24 hours to dry out before wearing them again
protecting your feet in public swimming pools or showers by wearing flip-flops
using talcum power on your feet to minimize moisture
checking regularly in the spaces between your toes for new infections
staying in good overall health, including eating right, and exercising regularly
treating your shoes with an antifungal agent if you've had an infection
not sharing shoes, towels, or socks with others